Abstract:

Responses of biological indicators of soil quality to winter cover cropping were
measured on soil samples collected from 6 commercial growers' fields and two
experiment research stations in the Willamette Valley of Oregon. The research stations
were the North Willamette Research and Extension Center (Aurora, OR), and the
Oregon State University Vegetable Farm (Corvallis, OR). The research stations and
five on-farm sites compared winter cover crops or winter fallow in rotation with a
summer vegetable crop. In one on-farm site, minimum tillage or conventional till
following winter cover crops was compared. The objectives of this study were to:
1) monitor changes in soil biological properties under field managed with cover crops;
2) test potential of buried cotton strip as indicator of soil biological activity and as a soil
quality index; and 3) assess the degree of correlation between tensile strength and
cotton strip weight loss. The major findings were: 1) microbial biomass carbon and
β-glucosidase activity were the most sensitive to cover crop management; 2) cotton strip
decomposition was correlated to soil biological properties but was not very sensitive to
management changes; and 3) that measuring weight loss was nearly as effective as
tensile strength in assessing cotton strip decomposition in soils.